Angularly adjustable auger head



Sept 1, 1970 D.E.ADK1NS ETAL 3,526,285

ANGULARLY ADJUSTABLE AUGER HEAD- r Filed Nov. 5, 1968 United States Patent O1 tice 3,526,285 ANGULARLY ADJUSTABLE AUGER HEAD David E. Adkins and Ronald L. Legue, Columbus, Ohio,

assignors to American Gas Association, Inc., New

York, N.Y., a corporation of New York Filed Nov. 5, 1968, Ser. No. 773,615 Int. Cl. E21b 7 04 U.S. Cl. 175-73 10 Claims ABSTRACT OF THE DISCLOSURE Directionally controllable horizontal earth boring apparatus including an auger, an auger head which carries a. pilot bit, a casing which is fed into the bore with the auger, and a mechanism for tilting the head relative to the auger axis. The tilting mechanism comprises a universal joint, which couples the auger to the head assembly, and a position plate-bearing assembly, which causes angular head movement in response to energization of a hydraulic actuator.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to earth boring. More particularly, the present invention relates to the directional control of horizontal earth boring tools. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.

Description of the prior art Utility companies have long recognized the costly labor expense and public opposition associated -with the prior art method of installing distribution lines in excavated trenches. These problems have, of course, been aggravated when the breaking of pavement or the interruption of railway service was involved. The disadvantages inherent in trenching can be signicantly reduced by using horizontal earth boring tools for installing underground cables and conduits and accordingly horizontal augering has in recent years been specified in many situations requiring the placement of utility lines under roads and railroads.

Prior art horizontal augering equipment has, however, been plagued with a serious problem. This problem resides in the previously existing inability to exercise control over the direction of the drill string so that the drill may be redirected should it deviate from the correct drilling path. As is known, unpredictable drift in underground boring operations is caused by the flexibility of the boring tool. It is extremely dilicult to make such tools stiff or rigid enough to withstand lateral thrust loads imposed on the drill head or bit by stone, other soil discontinuities, or even by the rotational torque transmitted to the drill string from the driving apparatus.

The above-noted deection or drift phenomenon has been most pronounced when the ratio of drill string length to drill string diameter becomes large. In addition, since the location of the boring bit is not always readily apparent, the drill string may drift as much as six feet in 100 feet or more before being noticed and corrective measures attempted.

In the prior art, the only directional control available is the use of pick up or pot holes located at intervals along the desired tunnel path, the bit being realigned if necessary as it passes each of the pick up holes. This technique is, however, only elective when bores are attempted without a casing and many times drill string deflection between pick up holes or too slight to be visually noticed at pickup holes will make it dicult to later insert a casing or carrier pipe. Also, the use of pickup 3,526,285 Patented Sept. 1, 1970 holes is subject to the same public opposition, albeit to a lesser degree, as trenching.

It has been recognized that a more accurate method for underground installation of a conduit encompasses augering through a casing while simultaneously jacking the casing. However, this method will also fail when a drill string is deflected since the auger will bind in the casing. Such binding sometimes results in a loss of a section of auger as well as loss of time spent in partially completing the tunnel.

In the drilling of wells, for example oil wells, techniques have been evolved for the directional control of the drill string. These techniques, however, are primarily of use in the drilling of slant bores and, for numerous reasons, are not suitable for the exercise of directional control over horizontal boring tools where the ability to compensate for unwanted bore hole deviation in any direction is necessary.

SUMMARY OF THE INVENTION The present invention overcomes the above-discussed and other disadvantages of the prior art and, in so doing, provides for the redirection of a horizontal augering tool when it drifts or is forced from the desired drilling path. In achieving these desired improved results, the present invention employs an auger head which may be tilted in any horizontal azimuth angle in order to accomplish redirection of the auger. The tilting of the auger head, which carries a pilot bit and a plurality of forward facing cutter teeth, is achieved through the use of a wobble plate and universal joint assembly. Rotational motion of the auger is transmitted to the auger head via the universal joint and plate. A cutter bearing is attached to the auger head to facilitate rotation thereof. The cutter bearing rides on a cylindrical, forward extension of a movable position plate. The position plate is capable of being tilted by virtue of a hemispherical bearing surface disposed between a portion thereof and the forward section of the casing which is fed into the bore hole with the auger. Also attached to the casing is a wrap-around cylinder having a movable piston therein. Piston rods extending out of the piston engage carn slots in the position plate. When it is desired to tilt the auger head, fluid under pressure is supplied to the cylinder thereby causing movement of the piston, the piston movement being transmitted to the position plate via the piston rods and cam slots. Longitudinal movement of the position plate is prevented by the auger head and thus movement of the piston will cause the position plate to rotate on the hemispherical bearing surface. This rotation or tilting of the position plate is transmitted to the auger head via the cutter bearing. Auger head tilting while cutting is continued is permitted through the use of the universal joint and wobble plate. The direction of auger head tilting may be controlled by rotating the casing to thereby vary the radial position of the piston rods and position plate cam slots.

BRIEF DESCRIPTION OF THE DRAWING The present invention may be better understood and its numerous advantages will become readily apparent to those skilled in the art by reference to the accompanying drawing wherein like reference numerals refer to` like elements in the various figures and in which:

FIG. 1 is a side elevation view, partly in section, of a preferred embodiment of the present invention.

FIG. 2 is an enlarged, top view of the auger head assembly of the embodiment of FIG. l.

FIG. 3 is a side view, partly in section, of the auger head assembly of FIG. 2.

FIG. 4 is a front, elevation view of the auger head assembly of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to FIG. l, the apparatus for the redirection of a horizontal earth boring tool of the present invention comprises a tiltable, auger head assembly. The auger head itself, indicated generally at 10, carries a pilot bit 12 and a plurality of forward facing cutter teeth 14. The overall shape of the cutting portion of the auger head may best be seen from FIG. 4. Auger head also comprises a wobble plate 16 to which the actual cutting tool is affixed.

As will be described in greater detail below, auger head 10 is coupled to the auger, indicated generally at 18, via a universal joint and thus the auger head will rotate with the auger. Auger 18 rotates within a casing 20 which is jacked forward section 22 which supports an actuating mechanism which will also be described in detail below. While not shown as such in order to simplify the drawing and thus to facilitate understanding of the present invention, casing section 22 is intended for reuse and will typically be attached to the remainder of the casing by means of a diametral tongue and groove assembly with a series of studs to hold it in place. Quick disconnect fittings would fbe provided for the hydraulic lines, which will be discussed below.

The auger 10 has a tubular support shaft or auger pipe 24 which is supported at the end opposite to head assembly 10 by means of a pair of 'bearings 26 and 28. The auger is driven, via a drive coupling 30, by means of a sprocket 32 and chain drive, not shown, which is connected to a rotary drive mechanism, also not shown. Bearings 26 and 28 are mounted on a slidin-g frame 34 and thus, upon disconnecting of the drive coupling 30, the bearings may be moved axially of the auger. The details of drive coupling 30 do not comprise part of the present invention and thus have been omitted from the drawing in the interest of clarity. However, drive coupling 30 is comprised of a male octagonal member fitting into a female octagonal member tted with a shear screw to prohibit axial motion. Accordingly, as the bore progresses, additional sections or lengths of auger and casing may be coupled to the apparatus to thereby extend the hole.

The rotary drive mechanism for auger 18 wouldeither be mounted on frame 34 or elsewhere and would move with the frame. The means for moving frame 34 and thus the means for urging the auger forward and jacking the casing into the bore hole will consist of the force from a large hydraulic cylinder, not shown, rigidly attached to the rotary drive mechanism or to the sliding frame 34. The cylinder exerts its force against the track upon which the frame slides thereby pushing the frame, casing and auge; apparatus forward with respect to the stationary trac It is to be noted that a pair of fluid supply lines 36 and 38 will extend along the length of the casing 200 rearwardly from forward casing section 22. Supply lines 36 and 38 will be attached to the exterior of casing 20 by any suitable technique, for example by being tack welded, the sections of casing typically being fabricated with the hydraulic lines thereon. Supply lines 36 and 38 will be provided with suitable ttings adjacent the ends of each section of auger casing so as to enable the extension of the lines as the casin-g is extended. The ends of the fluid supply lines adjacent drive coupling 30 will be connected to a suitable source of pressurized fluid 40 by means of a control valve 42 and flexible extensions 36 and 38 of lines 36 and 3-8. Control valve 42 may be a four-Way spool valve.

The manner in which the control system compensates erated in response to the sensing of undesired auger drift. In order to sense such drift, a forward section of tubular auger pipe 24 may contain suitable sensors for detecting the direction of motion of the auger. These sensors do not form a part of the present invention and will not be described herein. However, it is to be noted that the sensors in the instrumented auger pipe section will detect undesired drift of the auger and provide signals commensurate therewith. These signals commensurate with drift may be either applied to suitable indicators so as to enable the exercise of manual control over valve 42 or the drift signals may be employed to automatically control the fluid supply system of the present invention to thereby cause proper corrective action.

The above-described corrective action is achieved by means of tilting the auger head 10 in the proper direction to redirect the auger should it be deflected. The tilting of auger head 10 is caused by the motion of a position plate, indicated generally at 44, which has a pair of rearwardly extending arms 46 disposed along opposite sides of casing section 22, Position plate 44 also comprises a cylindrical forward section 48. It is especially to be noted that position plate arms 46 are provided with cam slots 50 which are engaged by piston rods as will be described below.

The means for coupling the rotational motion of the auger 18 to auger head 10 may best be seen from a simultaneous consideration of FIGS. 2 and 3. The forward end of auger 18 is coupled to the wobble plate 16 via a universal joint, indicated generally at 52. The rotary a-uger motion coupled through universal joint 52 is transmitted to the auger head by wobble plate 16, the wobble plate being attached in any suitable manner to shaft extension 54 which extends forwardly from universal joint 52. In order to prevent fouling of universal joint 52 by dirt being carried back into the auger, if deemed necessary or desirable, a wedged universal housing can be employed to extrude collected dirt when the joint is in motion, or a suitable protective cover may be used.

Wobble plate 16 is bolted or otherwise attached to a cutter bearing 56, which typically will be comprised of Oilite bronze, and thus the auger head 10 will rotate on bearing 56. As may be seen from FIG. 3, bearing S6 rides on a flanged bearing surface provided in cylindrical position plate extension 48.

`Continuing with a consideration of FIG. 3, it may be seen that the inner surface of cylindrical position plate extension 48 comprises a hemispherical bearing surface which is complementary with a bearing surface 58 on the forward end of casing section 22. If found to be necessary, a cladding or slip grommet may be used to prevent marring of the hemispherical bearing surface 58 during forward motion of the casing with the auger head tilted at a corrective angle.

Casing section 22 also has, either mounted thereon or formed as a part thereof, a wrap-around hydraulic cylinder 60 which contains a piston 62. Piston 62 has a pair of oppositely disposed, outwardly extending piston rods, only one of which 64 is shown. Piston rods 64, as previously noted, are disposed in and engage the walls of cam slots 50 in position plate arms 46. Fluid supply line 36 is in communication with cylinder 60 to the rear of piston 62 while fluid supply line 38 is in communication with cylinder 60 adjacent the forward end thereof.

When a directional correction is necessary, the proper one of lines 36 or 38 will be placed in communication with high pressure fluid source 40 via valve 42. Considering FIGS. 1 and 3, line 36 is the forward or tilt down ow line while line 38 is the rearward or tilt up ilow line. If valve 42 places line 36 in communication with pressurized source 40, any fluid trapped in cylinder 60 in front of piston 62 will be bled off va hydrualic line 38. Piston 62 will thus move in the forward direction, the amount of forward movement being controllable by means of regulating the pressures at the opposite sides of piston 62. Forward movement of piston 62 results in axial movement of piston rods 64. Since piston rods 64 are in engagement with cam slots 50 of position plate 44, forward movement of piston 62 will cause tilting of the position plate, the tilting resulting in rotational motion between hemispherical bearing surface 58 and the complementary bearing surface on cylindrical position plate extension 48. The tilting of the position plate 44 is transmitted to the auger head 10 via bearing 56 which is rotating on the cylindrical position plate extension 48. Thus, the auger hed will also tilt. The tilting of the auger head will, of course, be permitted by universal joint S2 and auger head 10 will continue to rotate and lengthen the bore hole. When the desired directional correction has been achieved, the uid connections established by valve 42 will be reversed and piston 62 will be returned to its starting point. Return of piston 62 will result in the straightening ofthe movable position plate and auger head. l

As should be obvious, the casing 20 must be rotated to the position which will enable tilting of the auger head in the proper correctional azimuth angle. Rotation of the casing may b e accomplished :by use of a two piece, selftightening chuck with sprockets around the circumference. The chuck will, of course, be installed on an exposed portion of the casing and rotational torque will be supplied by a chain drive from an auxiliary motor. Alternatively, the chuck can be'turned by a power takeoff from the boring machine.

In practice, a two inch diameter universal joint may be employed and auger head tilting to a maximum of five degrees (either up or down), from the centerline of the auger has been possible. The` tilting can be commanded by the delivery of hydraulicgfiuid to the wrap-around cylinder, such fiuid being sufficiently pressurized to supply 19,000 pounds of force to the position plate.

While a preferred embodiment has been shown and described, various modifications and substitutions may be made thereto without departing from thhe spirit and scope of the present invention. Accordingly, it is to be l. understood that the present invention has been described by way of illustration and not limitation.

What is claimed is: 1. Directionally controllable earth boring apparatus comprising:

an elongated rotatable auger; an auger head; a bore hole casing coaxial with said auger; means for coupling rotational motion of said auger to said head, said motion coupling means permitting angular adjustment of said head relative to the axis of the auger; bearing means disposed between said casing and said head, said head rotating on said bearing means; fluid operated actuating means on said casing; and means for transmitting motion of said actuating means to said auger head to cause angular repositioning thereof as the head continues to rotate on said bearing means. 2. The apparatus of claim 1 wherein said actuator motion transmitting means comprises:

means for changing the angle of attack of said bearing means.

3. The apparatus of claim 1 wherein said bearing mearfs comprises:

a first bearing afiixed to said head;

position plate means providing a first bearing surface for said first bearing, said position plate nieans being connected to said actuator motion transmitting means and providing a second bearing surface; and

a hemispherical bearing surface on said casing, said position plate second bearing surface riding on said hemispherical bearing surface.

4.1The apparatus of claim 3 wherein said actuator motion transmitting means comprises:

means for angularly adjusting said position plate means.

5. The apparatus of claim 4 wherein said position plate means comprises:

a cylindrical forward section which defines said first and second bearing surfaces at opposite ends therevof; and

rearwardly extending arm means, said arms means having at least a first cam slot therein.

`6. The apparatus of claim 5 wherein said actuating means comprises:

an hydraulic cylinder having a movable' piston disposed therein.

7. The apparatus of claim k6 wherein said means for angularly adjusting said position plate comprises:

a piston rod connected at one end to said movable piston and having its other end disposed in said cam slot.

8. The apparatus `of claim 7 wherein said means for coupling rotational motion to said head comprises:

a wobble plate affixed to said head; and

universal joint means connecting said auger to said wobble plate.

9. The `apparatus of claim 2 wherein said means for coupling rotational motion to said head comprises:

a wobble plate afiixed to said head; and

universal joint means connecting said auger to said wobble plate.

10. The apparatus of claim 8 wherein said first bearing is'attached 4to said wobble plate for rotation therewith.

References Cited UNITED STATES PATENTS 2,119,095 5/ 1938 -Brummett 175-73 2,581,667 1/1952 Joy 175-62 X 2,675,213 4/1954 Poole 175-62 X 3,326,008 6/ 1967 Baran 175-61 X 3,330,368 7/1967 Baran 175-94 3,354,969 11/ 1967 Ebeling 175-62 X 3,375,885 4/1968 Scott 175-26 3,402,781 9/ 1968 Sandberg 175-62 X NILE C. BYERS, JR., Primary Examiner U.S.Cl.X.R. --62 gyg@ UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,526,285 Dated September l, 1970 Inventods) David E. Adkins and Ronald L. Legue It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 16, after "jacked" insert --into the bore hole as the hole is extended.' Casing 20 has a;

line 56, change "200" to -20.

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